Ways of fixing wooden floor beams. Interfloor wooden beams

The growth in the volume of private housing construction indicates an increase in the well-being of our compatriots. To the younger generation It is hard to believe that not so long ago it was necessary to be on the waiting list for 30-40 years for housing, and the result of the waiting was still unknown. Even those who had the opportunity to immediately pay for cooperative housing had to sign up as members of these communities through a large pull, the volumes of such construction were scanty. This is a reference for those who idealize the times of the USSR too much, but did not live then.

Today the situation has changed dramatically, a large number of our compatriots can buy ready-made apartments in high-rise buildings, and those who do not want to breathe city smog are being built outside the city. Building materials and technologies existing on the market make it possible to create unique projects, architects could not even dream of such before. But not all developers have enough knowledge to choose the right option on the second floor. Let's try to figure it out.

Depending on the features of the building project, there are two types of floors on the second floor on wooden beams.

SNiP 2.03.13-88 of 01.01.1989 Floors. Thickness, floor coverings, interlayer, screed and subfloors(click on the link to open the PDF file in a new window).

Table. Types of floors on the second floor on wooden beams.

In what cases is it recommended to lay cold floors on the second floor

To convincingly answer this question, we must recall a few elementary rules of heat engineering.

Most professional builders strongly do not recommend making insulated floors on the second floor if its premises are used as residential. You need to know that in addition to unnecessary losses of money and thermal energy, another problem may appear. In case of violation of technology thermal insulation material increases its humidity, all wooden elements are operated in a very difficult conditions. Heat plus moisture is an excellent environment for the development of fungi and rot on carriers wooden elements, and no state-of-the-art impregnations can protect them for a long time. Over time, we have to deal with very unpleasant premature repairs. We hope that this information will help you make the best decisions in each specific case.

General requirements

Regardless of the specific features of the floor, building codes put forward for all structures General requirements. Only their implementation guarantees long-term and efficient operation of structures.

insulation

Among the many types, two are most often used: mineral wool and. Which to choose? The answer to the question should be sought by each developer on their own, we only give our recommendations.

1. . It can be rolled or pressed, it has replaced traditional glass wool. It has two real advantages: it does not burn and does not release harmful chemical compounds into the air. Disadvantages: high price, relatively large weight and hygroscopicity. The last drawback requires special attention. The fact is that cotton wool absorbs moisture very quickly and dries for a long period of time. This means that wooden floor structures are constantly operated in conditions high humidity, and this has an extremely negative effect on durability. Another problem of hygroscopicity - wet cotton wool dramatically increases the thermal conductivity, the efficiency of insulation decreases markedly.

   

   

2. . Many consumers are wary of this material, the consequences of anti-advertising of competitors are affecting. Like, it burns and emits aggressive chemical compounds. Such anti-advertising is spread by manufacturers of mineral wool, they have their own personal economic goals. What is real? Modern foam plastic is manufactured using innovative additives, due to this, the amount of harmful substances emitted has decreased to a normalized permissible level. According to these parameters, there are no strict restrictions for polystyrene foam; by the way, it is less toxic than some varnishes used to make furniture. Another little-known quality - modern foam does not support open combustion, this is very important characteristic all building materials. Of course, foam plastic is much inferior to mineral wool in terms of fire safety, but this is not as critical as it might seem. In practice, no one has yet seen the whole house burn down, and the floor with mineral wool remained safe and sound. And vice versa, firefighters did not observe a situation when only one floor with foam insulation burned down, and all other structures were not affected by the fire. In case of fire, there is no big difference with what material you insulated the floor of the second floor, the house will completely burn down anyway. But at the cost of manufacturability and durability of operation, floors with foam insulation are much superior to designs with mineral wool.

   

   

These are objective comparative characteristics two heaters, analyze the information and draw your own conclusions.

floor beams

Depending on the planned loads, boards 50 × 200 mm, 50 × 250 mm or bars of at least 150 × 150 mm can be used. It is necessary to choose only high-quality lumber not lower than the first grade. When calculating, it should be taken into account that the load on square meter floor can reach 210 kg, and the maximum deflection should not be more than 1/250 of the length. For example, if the length of a room on the second floor is 5 m, then the deflection in its center cannot be more than 2 cm. This is the maximum value, in some cases the deflection cannot exceed 1/400 of the length.

Beams and ceilings must withstand up to 180 kg / sq. m load

A beam section of 15x15 will be enough

Beams follow in without fail impregnate with modern antiseptics, all places of contact between wood and concrete or masonry building materials are waterproofed. And most importantly, the presence of a constant and effective ventilation spaces under the floor. This is the only way to ensure optimal conditions operation of load-bearing wooden structures.

Soundproofing

Existing regulations prescribe that the sound insulation threshold of interfloor ceilings should not exceed 50 dB. It is known from physics that the greater the density of a material, the better it conducts vibrations. Sound is air vibrations, air waves of various lengths and intensities. All insulation materials perfectly extinguish them; to achieve the required standards, it is enough to make a layer of mineral wool or polystyrene 50 mm thick between floors.

Maximum length of wooden beams

The floor can not be laid on fragile bases, and lumber has its limitations. Modern wooden channels can cover spans up to ten meters, unfortunately, beams cannot be used in such situations. They are allowed to be used with a span of no more than 5 m for interfloor floors and no more than 6 m for attic floors. But the length of 4 m is considered optimal, with a further increase in the distance between the stops, the deflection under its own weight increases significantly. In connection with such features, the beams must be laid across the width of the room, the step between them depends on several initial data: in the first place is the load per square meter, in the second place is the convenience of laying heat-insulating materials. To facilitate the selection process, building codes and regulations have tables with recommended beam sizes, taking into account the span of the floor.

Type and materials of flooring

There are several options for arrangement, while choosing a specific one, it is recommended to take into account the maximum number of individual factors.

Natural boards or soft coatings can be used as finishing materials. But there is one limitation. If underfloor heating is planned, then wooden materials should not be used for two reasons. Firstly, they react extremely negatively to high temperatures and will definitely crack. Secondly, the tree has a low thermal conductivity, which impairs the heating efficiency.

Video - Draft floor. Floor device in a wooden house

Waterproofing materials

They should only be used when laying underfloor heating with mineral wool. Where exactly and what kind of waterproofing is used?

If the room has underfloor heating, then the installation process is even more complicated. between insulation and heating element there is an additional reason. It greatly complicates the process of natural ventilation and worsens the operating conditions of wooden structures. This must be remembered before starting work with the floor, it is necessary to foresee the consequences of the decisions made.

Step by step instructions for building a floor

For example, we will take difficult option- floor insulated with mineral wool. Floor beams from boards 50 × 200 mm, according to calculations, such elements fully withstand the planned loads and have a safety margin of approximately 40%. The reserve is obligatory for all critical architectural elements of buildings, the ceiling is included in the list of such structures. For vapor barrier, modern membrane coatings, rough floor from edged boards 20 mm thick.

Practical advice. In order to reduce the cost of construction, OSB or plywood boards, used boards of the same thickness or various substandard segments can be used for the subfloor. The decision should be made taking into account personal financial capabilities and the type of finish flooring.

Step 1. Lay the floor beams on the load-bearing walls. We have already said that in order to reduce the deflection force, they should be laid along the width of the room, and not along the length. Be sure to wrap the ends of the beams with roofing material, there must be at least two layers. The boards themselves are recommended to be impregnated at least twice with an antiseptic. The specific brand does not matter, they all do their job quite effectively, except for obvious counterfeit products. The distance between the beams corresponds to the width of the mineral wool sheets. Standard materials have a width of 60 cm, which means the distance along the axes of the beams is also 60 cm. Thus, a clean niche of 55 cm wide is obtained, this allows you to tightly insert mineral wool and eliminate the appearance of cracks. Slots are undesirable not only because they cause heat loss. There is another problem - condensation is constantly present in these places, the tree gets wet and begins to rot. It makes no sense to talk about the negative consequences of such a process.

Options for fixing floor beams to wooden walls

There are quite a few ways experienced builders make the final decision on site. Beginners can be recommended to use one of the listed methods.

1. At the ends of the beams, recesses are made for the dimensions of the logs.. Advantages - the beams lie firmly on the wall, in many cases additional fixation is not required. Disadvantages - the trimmed elements lose their strength, it takes quite a lot of time to prepare each beam. During the calculations, it is necessary to take into account not the total width, but only in the place of the undercut. And there it is significantly reduced, due to which the consumption of lumber increases.
2. The ends of the beams lie on the log line, special openings are made under them. A very simple and time-tested method, universal application. Professional builders always try to use this method of mounting the second floor floor beams.

   

3. With the help of metal special fasteners. They are matched to the size of the beam and screwed or nailed to the inner surfaces. facade walls. Beams are inserted into seats. The advantages of the method are simplicity and ease of installation. Disadvantages - the bearing capacity is reduced, the mount is the weakest point and cannot withstand the same loads as the beam.

   

   

Step 2 Fix the steam protection to the lower planes of the beams with a stapler. An overlap of at least ten centimeters, all joints must be sealed with adhesive tape. We have already mentioned that it will not be possible to make a sealed cavity, moisture will find gaps in any case. But this does not mean that it is unnecessary to take measures to minimize this process.

Step 3 Nail slats or boards to the bottom of the beams. The finishing of the final ceiling will be fixed to them, the base must be strong. Thermal insulation material is laid on top of the rails. In our case, this is mineral wool, make sure that it fits snugly against the edges of the niche.

Practical advice. The thickness of the insulation is recommended at least ten centimeters. It is much more efficient to lay not one layer of insulation of this thickness, but two five centimeters each. Due to this, it is possible to make displacements of the joints and completely eliminate the likelihood of cold bridges.

It is very important that the mineral wool does not get wet, if the house does not have a roof, then it must be protected with a film. Wet material cannot dry on its own in a niche; it must be removed for drying. And this is not only unplanned loss of time, but also a large amount of unproductive waste. During dismantling, wet cotton wool is easily torn, some sheets must be completely replaced with new ones. As a rule, no one plans such losses and does not take into account when calculating the amount of insulation. As a result, a second visit to the building supplies store is required.

Step 4 Lay waterproofing on top of the insulation. We have already mentioned that for these purposes it is necessary to use only a special innovative membrane, it allows steam to pass through and retains water. The membrane is also overlapped and fixed with a stapler.

Step 5 Lay the subfloor. Laminate is chosen as the topcoat, and a solid base is required under it. Nail the boards tightly, but there is no need to specifically tighten with wedges. Gaps of no more than one centimeter are allowed. At least two nails must be driven into each board on each side, otherwise they will definitely bend during operation. This is a very undesirable phenomenon, especially for a laminate - a light coating rises, extremely unpleasant squeaks appear when walking.

It is not easy to eliminate them, you need to completely remove the laminate, level the subfloor boards and re-lay the coating again. As practice shows, it is much more profitable both economically and in time to strictly observe the recommended technologies than to eliminate the admitted marriage later.

The draft floor on the second floor is ready, you can continue the construction of the facade walls. Finishing covered is allowed only after the completion of the installation of the roof, finishing the ceiling and walls.

Prices for floor boards

floor boards

Video - Wooden floor insulation

Video - Laying the floor on wooden beams on the second floor

How the length of wooden floor beams is determined: FORUMHOUSE experts talk about the nuances of calculation and self-production.

The possibility of unsupported overlapping of large areas greatly expands the architectural possibilities when designing a house. A positive solution to the beam issue allows you to "play" with the volume of rooms, install panoramic windows, build large halls. But if it is not difficult to block a distance of 3-4 meters with a “tree”, then which beams to use on a span of 5 m or more is already a difficult question.

Wooden floor beams - dimensions and loads

Made a wood floor log house, and the floor is shaking, bending, the “trampoline” effect has appeared; want to do wooden beams overlapping 7 meters; you need to block the room with a length of 6.8 meters so as not to rest the logs on intermediate supports; what should be the floor beam for a span of 6 meters, a house made of timber; what to do if you want to make a free layout - such questions are often asked by members of the forum.

Maxinova FORUMHOUSE user

My house is about 10x10 meters. I “threw” wooden logs onto the ceiling, their length is 5 meters, the section is 200x50. The distance between the lags is 60 cm. During the operation of the floor, it turned out that when the children run in one room and you stand in another, there is quite a strong vibration on the floor.

And this case is far from the only one.

elena555 FORUMHOUSE user

I can’t figure out which beams for interfloor ceilings are needed. My house is 12x12 meters, 2-storey. The first floor is made of aerated concrete, the second floor is attic, wooden, covered with a bar 6000x150x200mm, laid every 80 cm. The logs are laid on an I-beam, which rests on a pole installed in the middle of the first floor. When I walk on the second floor, I feel shaking.

Beams for long spans must withstand heavy loads, therefore, in order to build a strong and reliable wooden floor with a large span, they must be carefully calculated. First of all, it is necessary to understand what kind of load a wooden log of one or another section can withstand. And then think over, having determined the load for the floor beam, what kind of rough and finish flooring will need to be done; what will the ceiling be hemmed with; whether the floor will be a full-fledged living space or a non-residential attic above the garage.

Leo060147 FORUMHOUSE user

1. The load from the own weight of all structural elements of the floor. This includes the weight of beams, insulation, fasteners, flooring, ceiling, etc.
2. operating load. The operating load can be permanent or temporary.

When calculating the operating load, the mass of people, furniture, household appliances, etc. is taken into account. The load temporarily increases with the arrival of guests, noisy celebrations, rearrangement of furniture, if it is moved away from the walls to the center of the room.

Therefore, when calculating the operational load, it is necessary to think through everything - up to what furniture is planned to be installed, and whether there is a possibility of installing a sports simulator in the future, which also weighs far more than one kilogram.

For the load acting on the wooden beams of a floor of great length, the following values ​​\u200b\u200bare taken (for attic and interfloor floors):

• Attic floor - 150 kg / sq.m. Where (according to SNiP 2.01.07-85), taking into account the safety factor - 50 kg / sq.m - this is the load from the floor's own weight, and 100 kg / sq.m - the standard load.

If it is planned to store things, materials and other household items in the attic, then the load is assumed to be 250 kg / sq.m.

• For interfloor floors and ceilings attic floor the total load is taken from the calculation of 350-400 kg / sq.m.

Overlapping boards 200 by 50 and other running sizes

These are the beams on a span of 4 meters that are allowed by the regulations.

Most often, in the construction of wooden floors, boards and timber of the so-called running sizes are used: 50x150, 50x200, 100x150, etc. Such beams satisfy the standards ( after calculation), if it is planned to block the opening no more than four meters.

For overlapping with a length of 6 meters or more, the dimensions 50x150, 50x200, 100x150 are no longer suitable.

Wooden beam over 6 meters: subtleties

A beam for a span of 6 meters or more should not be made of timber and boards of running sizes.

You should remember the rule: the strength and rigidity of the floor to a greater extent depend on the height of the beam and, to a lesser extent, on its width.

A distributed and concentrated load acts on the floor beam. Therefore, wooden beams for large spans are not designed "end-to-end", but with a margin of strength and allowable deflection. This ensures normal and safe operation of the ceiling.

50x200 - overlap for an opening of 4 and 5 meters.

To calculate the load that the overlap will withstand, you must have the appropriate knowledge. In order not to delve into the strength of materials formulas (and this is definitely redundant when building a garage), it is enough for an ordinary developer to use online calculators for calculating wooden single-span beams.

Leo060147 FORUMHOUSE user

A self-builder is most often not a professional designer. All he wants to know is which beams need to be installed in the ceiling so that it meets the basic requirements for strength and reliability. This is what online calculators allow you to calculate.

These calculators are easy to use. To make calculations required values, it is enough to enter the dimensions of the lag and the length of the span, which they must cover.

Also, to simplify the task, you can use ready-made tables presented by the gurus of our forum with the nickname Roracotta.

Roracotta FORUMHOUSE user

I spent several evenings to make tables that even a novice builder will understand:

Table 1. It presents data that meet the minimum load requirements for the floors of the second floor - 147kg / sq.m.

Note: since the tables are based on American standards, and the dimensions of lumber overseas are somewhat different from the sections adopted in our country, the column highlighted in yellow should be used in the calculations.

Table 2. Here are the data on the average load for the floors of the first and second floors - 293 kg / sq.m.

Table 3. Here are the data for the calculated increased load of 365 kg / sq.m.

How to calculate the distance between I-beams

If you carefully read the tables presented above, it becomes clear that with an increase in the length of the span, first of all, it is necessary to increase the height of the log, and not its width.

Leo060147 FORUMHOUSE user

You can change the stiffness and strength of the lag upwards by increasing its height and making “shelves”. That is, a wooden I-beam is being made.

Independent production of a wooden glued beam

One solution for long span spans is the use of timber beams in the spans. Consider a span of 6 meters - which beams can withstand a large load.

According to the type of cross section, a long beam can be:

• rectangular;
• I-beam;
• box-shaped.

There is no consensus among self-builders which section is better. If you do not take into account purchased products (prefabricated I-beams), then the simplicity of manufacturing in the "field conditions" comes first, without the use of expensive equipment and rigging.

Just Grandpa FORUMHOUSE user

If you look at the cross section of any metal I-beam, you can see that from 85% to 90% of the mass of the metal is concentrated in the "shelves". The bonding wall accounts for no more than 10-15% of the metal. This is done on the basis of calculation.

What board to use for beams

According to the strength of materials: the larger the section of the “shelves” and the further they are spaced from each other in height, the greater the load the I-beam will withstand. For a self-builder, the optimal technology for manufacturing an I-beam is a simple box-shaped design, where the upper and lower "shelves" are made of a board laid flat. (50x150mm, and the side walls are made of plywood with a thickness of 8-12 mm and a height of 350 to 400 mm (determined by calculation), etc.).

Plywood is nailed to the shelves or screwed with self-tapping screws (only not black, they do not cut) and must be glued.

If you install such an I-beam on a six-meter span in increments of 60 cm, then it will withstand a large load. Additionally, an I-beam for a ceiling of 6 meters can be laid with a heater.

Also, using a similar principle, you can connect two long boards, assembling them into a “package”, and then put them on top of each other on an edge (take boards at 150x50 or 200x50), as a result, the cross section of the beam will be 300x100 or 400x100 mm. The boards are planted on glue and pulled together with studs or planted on capercaillie / dowels. You can also screw or nail plywood to the side surfaces of such a beam, having previously lubricated it with glue.

Also interesting is the experience of a forum member under the nickname Taras174, who decided to independently make a glued I-beam to block a span of 8 meters.

To do this, the forum member purchased OSB sheets 12 mm thick, cut them lengthwise into five equal parts. Then I bought a board 150x50 mm, 8 meters long. With a dovetail cutter, I chose a groove in the middle of the board with a depth of 12 mm and a width of 14 mm - so that a trapezoid with an extension downwards was obtained. OSB in grooves Taras174 glued with the help of polyester resin (epoxy), having previously “shooted” a strip of fiberglass 5 mm wide to the end of the plate with a stapler. This, according to the forum member, would strengthen the design. To speed up drying, the glued area was heated with a heater.

Taras174 FORUMHOUSE user

On the first beam, I trained "filled my hand." The second one was done in 1 business day. At a cost, taking into account all materials, I include a solid board of 8 meters, the cost of a beam is 2000 rubles. for 1 piece

Despite the positive experience, such a "squatter" did not escape several criticisms made by our experts. Namely.

Ceilings between floors, basements or attics are structurally arranged according to two schemes - a beamless ceiling (based on the use of a monolithic slab), and a beam ceiling (wooden floor beams are used). They make ceilings to separate the interfloor premises, as well as to separate the rooms from the basement and attic. Beams can be made from various materials, for example, from wood, monolithic reinforced concrete or metal girders.

The installation of wooden floor beams allows you to solve the following problems:

1. achieve the required indicators of strength and rigidity of the overlap;


2. ensure that sound insulation and heat transfer resistance comply with the level required for energy saving;


3. maintain compliance with the established standards for vapor and air permeability.

The choice of beams for interfloor ceilings:

By type and type:

• Timber floor beams. Most often, for the manufacture of beams, a rectangular beam is chosen. The height of the beam should be in the range of 140-240 mm, and the thickness should be 50-160 mm. In this case, the rule is observed: the thickness of the beam is at least 1/24 of its length. Professionals note that greater strength is inherent in a wooden beam with an aspect ratio of 7:5.

• Log beams. More economical solution. The log has a high resistance to stress, but also low resistance to bending. The log is suitable for use only if it has been aged in dry conditions for at least one year.

• Floor beams from boards. The use of the board leads to a reduction in the amount of lumber consumed for the flooring device. But, it is worth noting that in this case, the resistance of the ceiling to fire, durability and sound insulation are reduced. Usually the board is used in the construction of attic floors. To strengthen the boards, you can use the technique - to splice two boards together along the length. Then the total cross section will correspond to the load level. This design can withstand a load 2 times greater than a beam or two boards laid close to each other. In this case, fastening is carried out with self-tapping screws or nails fixed in a checkerboard pattern with a step of 20 cm.

2. Acquisition of timber, logs or lumber and its treatment with an antiseptic, fire-fighting, anti-fungal solution and biological protection.

3. Choice of the type of fastening of the beam to the wall.

Fastening wooden floor beams to the load-bearing wall is carried out in two ways:

• wall mounting. The beam is embedded in bearing wall to a depth of 150-200 mm.

With this method of installation, the end of the beam must be cut at an angle of 60 °. To protect the ends of the beam, they need to be wrapped in two or three layers of roofing material. In this case, the end of the beam remains open, and it should not rest against the wall. The presence of a gap of 20-25 mm. allow free air exchange. And the resulting niche (gap) is filled with mineral wool.

• hanging method. In this case, the beams are fixed on the wall by means of metal plates.

4. Laying wooden floor beams

At this stage, beams of the desired length are prepared. The length depends on the mounting method. If the beam is inserted into the wall, then it is calculated as follows: the length of the room plus 300-400 mm. for wall mounting. If attached to the wall, then the length of the beam is equal to the length of the room.

The installation of wooden floor beams begins with the extreme beams. Each beam is checked with a building level. After that, the beams are fixed in the sockets of the wall using dry crushed stone.

When the beams are set exactly in level and the horizontal is checked, they can be concreted in the landing slots.

Conclusion

Wooden beams made using this technology will reliably serve you for several decades. However, in order to prolong its service life, it is necessary to process the wood and carry out periodic inspection to control their condition. If there are defects, repair (partial or complete replacement of damaged elements).

Wooden floors(fig. 1) in most cases consist of load-bearing beams, floor, inter-beam filling and finishing layer of the ceiling. Sound or heat insulation is provided by a flooring, which is called a reel.

Beams are most often rectangular wooden beams. For reeling it is advisable to use wooden shields. In order to save wood, plank rolls can be replaced with rolls from ribbed or hollow gypsum or lightweight concrete blocks. Such elements are somewhat heavier than wooden rolls, but they are non-flammable and do not rot.
To ensure better sound insulation from airborne sound transfer along the reel, a clay-sand lubricant 20-30 mm thick is made, on top of which slag or dry calcined sand 6-8 cm thick is poured. The porous material backfill absorbs some of the sound waves.
The design of a wooden floor includes a flooring made of planed tongue-and-groove boards, nailed to the logs, from plates or boards, which are laid across the beams every 500-700 mm.

Wooden floor beams

The bearing elements of the beam ceilings are wooden beams of rectangular section with a height of 140-240 mm and a thickness of 50-160 mm, laid through 0.6; 0.8; 1 m. The cross section of the wooden floor beams depends on the load, filing (rolling) with backfill, and the plank floor laid on the logs as directly on the logs (Table 1.).

Table 1. Minimum section of wooden beams of a rectangular floor

The use of hardwoods as floor beams is not acceptable, as they do not work well in bending. Therefore, coniferous wood, peeled from bark and antiseptic without fail, is used as a material for the manufacture of wooden floor beams. Most often, the ends of the beams are inserted into nests specially left for this purpose in brick walls ah directly in the process of masonry ( rice. 2 a. or fig. 2 b.), or cut into the upper crown of log, block and frame-panel walls.

The length of the supporting ends of the beam must be at least 15 cm. The correct position of the extreme beams is checked by a level or spirit level, and the intermediate ones - by a rail and a template. The beams are leveled by placing tarred scraps of boards of different thicknesses under their ends. It is not recommended to lay chips or trim the ends of the beams.
Wooden floor beams are laid, as a rule, along a short span section, as parallel as possible to each other and with the same distance between them. The ends of the beams, resting on the outer walls, are cut obliquely at an angle of 60 degrees, antiseptic, burned or wrapped with two layers of roofing felt or roofing material. When embedding wooden beams into nests in brick walls, we recommend that the ends of the beams be treated with bitumen and dried to reduce the likelihood of rotting from moisture. The ends of the beams must be left open. Spatial niches when sealing wooden floor beams are filled around the beam with effective insulation (mineral wool, polystyrene). With a brick wall thickness of up to 2 bricks, the gaps between the ends of the beams and the brick wall are filled with cement mortar. It is also possible, as an option, to insulate the ends of the beams with wooden boxes, having previously tarred them. In thick walls (2.5 bricks or more), the ends of the beams are not covered, leaving ventilation holes. This prevents the ends of the beams from moisture condensation. Diffusion of moisture in a wooden beam is shown in fig. 3.

When supporting beams on internal walls two layers of roofing felt or roofing material are placed under their ends.
Every third beam embedded in the outer wall is fixed with an anchor. Anchors are attached to the beams from the sides or from the bottom and embedded in the brickwork.
In the absence of a beam of a suitable section, boards knocked together and placed on the edge can be used, while the total cross section, in comparison with the whole beam, should not decrease.

In addition, logs of the appropriate diameter, hewn on three sides, can be used instead of block beams, which is more economical (roundwood is much cheaper than lumber), but in this case the logs must be aged in a dry room for at least one year, like a log house.
To enhance the bearing capacity of the floor, a cross scheme for installing power beams can be used. When applying such a scheme, the floor rests on all the walls of the building along the contour. The nodes of the intersections of the beams are pulled together with clamps or wire twists. The cross-slab is used extremely rarely, since it is much easier to reduce the pitch of the supporting beams and make an ordinary floor, but less lumber is used to make a cross-slab than a traditional one, with the same load-bearing capacity of the floors.
Structural differences between floors are observed when they are insulated (Fig. 1.). The interfloor overlap is not insulated, the attic (with a cold attic) is insulated with the device of the lower vapor barrier layer, and the basement is insulated with the device of the upper vapor barrier layer.

Roll forward

The next step in the construction of floors is the roll-up flooring. For its fastening, cranial bars with a section of 5 x 5 cm are nailed to the beams, directly on which the rolling boards are laid. (Figure 4.)

The roll plates are tightly adjusted to each other, removing all the gaps between the individual boards. Strive to ensure that the lower surface of the roll is in the same plane as the floor beams. To do this, it is necessary to select a quarter (fold) in the roll-up boards. For the construction of the roll, it is not necessary to use full-fledged boards, they can be completely replaced with a croaker. The filing of boards with a thickness of 20-25 mm is fixed with nails hammered at an angle. As we have already noted, instead of boards for rolling, you can use fiberboard, gypsum slag and others easily. concrete plates, which increases the fire resistance of floors. The laid roll is covered with a layer of roofing felt or roofing material and filled or laid insulation: as in the walls, here you can use mineral wool, sawdust, slag. When insulating floors, loose insulation is not tamped, and they are backfilled at the height of the beams. The type of insulation and its thickness are determined from the calculated outdoor air temperature, using the data in Table 2.

Table 2. The thickness of the backfill of the attic floor, depending on the outside temperature

Lastly, the upper face of the beams is covered with roofing felt or roofing material, and logs are placed on top. Note that the lags are not a mandatory element of the overlap. Laying a log is economically justified if the beams have a rare arrangement.

We also draw your attention to what elements of the floors will be superfluous in the construction of basement and attic floors:
- there is no lining in the basement
- in the attic floor there is no log and a clean floor

The basement ceiling can be designed in such a way that the run-up and insulation will be superfluous (of course, without compromising performance), however, in this case, roofing material will be required over the entire floor area, and the backfill will be gravel or compacted rubble (Fig. 5.)

Chimney device (chimney)

In places where wooden floors come into contact with smoke channels, cutting is arranged (Fig. 6.)

The distance from the edge of the smoke channel to the nearest wooden structure is assumed to be at least 380 mm. Ceiling openings in the places where chimneys pass are sheathed with fireproof materials. In places of overlap in chimneys, cutting is arranged - thickening of the pipe walls. Within the cutting limits, the wall thickness of the chimney increases to 1 brick, that is, up to 25 cm. But even in this case, the floor beams should not touch brickwork pipes and stand at least 35 cm from the hot surface. This distance can be reduced to 30 cm by laying 3 mm thick felt or asbestos cardboard soaked in a clay solution between the groove and the beam. The end of the shortened beam, located opposite the groove, is supported on a crossbar suspended on clamps (Fig. 7.) to two adjacent beams.

Economic overlap

An economical floor is considered to be a floor consisting of wooden panels with one-sided and two-sided sheathing, which, together with the frame of the shields, perceives vertical loads. The sheathing can perform a load-bearing function only if it is firmly connected to the ribs of the boards of the shield frame. The ribs and skins are firmly connected to each other and have a high load-bearing capacity.

Chipboard and construction plywood proved to be excellent as cladding. Boards are also suitable for this, but, however, due to the large number of equally oriented seams, they do not contribute to an increase in the bearing capacity of the floor.

Gypsum fiber or gypsum boards cannot be considered as additional load-bearing elements. Not able to bear the load and sheet materials such as cement particle board and blockboard. In addition, they are much more expensive than chipboard and plywood. On fig. 8 shows several options for the arrangement of floors.

Rice. 8. .

Methods for calculating wooden floors

Previously, the load-bearing capacity of floors was determined by master builders, guided by their experience. Often this let them down, especially when erecting buildings of complex configuration, which led to the collapse of buildings.
In our time, computer technology has come to the aid of builders, providing, together with achievements in the field of materials science, high calculation accuracy. On fig. 9, as an example, the results of the calculation of the floors shown in fig. 8 .

It can be seen that despite the smaller thickness of the beams in the frame (by almost 40%), the shields can cover approximately the same spans as wooden beams. The maximum allowable width of the room and the width of the span in our case is about 6 m.

For single- and double-span structures, if the calculated values ​​are exceeded, additional supports are required under the ceiling, which significantly increases the cost of the structure.
For a single-span ceiling, where the shields lie on supports only with the ends of the stiffeners, the span width, which is somewhat larger than the clear width of the room, should not exceed approximately 5 m. For a double-span ceiling, the allowable span width and, accordingly, the room increases to 6 m.

In many projects offered by various companies, the depth of the house is determined by a two-span ceiling. The width between the longitudinal walls of the house usually ranges from 9 ... 12 m, and a load-bearing wall is placed in its middle. When calculating floor structures, first of all, its own weight is determined. In the variant shown in Fig. 9 , it is taken equal to 100 kg/sq.m., as is often the case. Additional load (weight of the inhabitants of the house and interior furnishings) take equal to 275 kg / sq.m.. Light partitions installed on the floor without any static calculations are also taken into account. Such a load could be created, for example, in a situation where, on a floor area of ​​20 sq.m. accommodate 73 people at the same time. This simple example shows that the regulatory indicators are focused on the unconditional safety of the inhabitants of the house. When calculating wooden structures, a triple margin of safety is usually provided, excluding the possibility of their collapse. In other words, in a room with a total area of ​​\u200b\u200b20 sq.m., that is, with dimensions of 5.90 x 3.40 m (see the allowable span width indicated in Fig. 9), 220 people could be accommodated, which, of course, just unrealistic. However, this example suggests that the calculated bearing capacity of the floor is so high that a fireplace, shelves, a tiled stove, a waterbed, an aquarium and much more can be safely placed on this floor.

Deflection limit under standard load

However, even under the normative load, the floor sags, which can be felt even when walking on it. To avoid these unpleasant sensations, the deflection of the ceiling must be no more than 1/300. This means that with a span width of 6 m, the floor can sag under the standard load (even if it occurs only in exceptional cases) no more than 2 cm.

Overlapping, of course, can bear a load no more than that which is allowed by loaded walls, lintels and supports. In this regard, a developer who does not have the appropriate specialized knowledge, who intends to place heavy structures or objects on the floor, should seek advice from a specialist in static calculations of the stability of building structures.
Overlapping gives the building additional rigidity. Wind loads acting on the building through the roof, on the gables and external walls, are transmitted through the ceiling to the entire structure of the building. To compensate for these loads, the upper cladding of the floor is strengthened. When laying individual floor beams, sheathing slabs (usually made of chipboard) are placed with mutual displacement of the seams and attached to the beams. When using ready-made floor elements, which is customary in the construction of prefabricated houses, they are firmly connected to each other, and along the edges - with a bearing support (walls, partitions).
If the size of the building on any of the facades exceeds 12.5 m, additional load-bearing partitions are required to give it the required rigidity. These walls must again be connected to the ceiling.

In contrast to the thermal insulation of the interfloor floor, which is of secondary importance, its sound insulation is given Special attention. Structures with good strength, unfortunately, do not always meet the requirements for noise protection. Designers working in the construction of prefabricated houses have to solve a controversial problem: the creation of statically reliable connections on the one hand, and on the other - and at the same time "soft" disconnected structures that provide optimal sound insulation.
Beams with rolling and filling with expanded clay or slag (Fig. 10 a, b) no longer meet the requirements either in terms of work technology, or in terms of sound insulation and a number of other problems.

The new standards were forced to include requirements for improving protection against impact noise, even to the detriment of the bearing capacity of structures. In order to jointly solve the problem of sound insulation, specialists from the field of prefabricated housing construction and the production of gypsum and insulating boards sat down at the same table. As a result, new designs were created, which were soon included in the norms (Fig. 11).

Rice. eleven. Overlapping options according to current standards with attenuation of airborne noise up to 52 ... 65 dB and shock - up to 7 ... 17 dB: 1 - grooved chipboard; 2 - wooden beams; 3 - gypsum boards; 4 - fibrous insulating board; 5 - fibrous insulating mat or plate; 6 - dry sand; 7 - rack lathing, in which the distance between the rails along the axes is 400 mm and fastened with spring brackets; 7a - wood boards; 8 - connections with self-tapping screws or glue; 9 - sound-absorbing floor covering; 10 - logs with a section of 40x60 mm; 11 - gypsum boards 12 - 18 mm thick or chipboard 10 ... 16 mm thick; 12 - concrete slabs laid on cold bitumen; 13 - sheathing from tongue-and-groove boards.

For the first time, the conversation turned to the use of the so-called spring brackets, which separate the beams and the lower cladding of the ceiling. (Fig. 12)

Practice has shown that this innovation has led to a decrease in the noise level by about 14 dB - a result that deserves attention. To improve sound insulation, it is necessary to place weighting agents inside the ceilings of this design, for example, sand, concrete slabs of various shapes and other materials that reduce the transmission of high-frequency sounds.
The disadvantages of backfilling with sand are the likelihood of it spilling through the seams and holes into the underlying rooms. But this can be prevented, for example, by laying a film or special mats. These mats consist of two films welded together, between which sand is located.
Instead of sand, cement-based boards can also be used. The disadvantage of these solutions is that such fillers are heavy, which requires more durable beams to the detriment of the cost-effectiveness of structures.
It is hardly possible today to make a ceiling with open (that is, not sheathed from below) wooden beams that would provide reliable noise protection. New Scientific research Unfortunately, they did not give positive results. So the question of the perfection of noise-protecting structures is waiting to be decided.

Weather protection

In special protection against climatic influences wooden structures outer wall, flat roof, ceilings of the attic (technical) floor or attic with sloping walls with a good roof are not needed. Protecting the same wood interfloor overlap important only in "wet" rooms (as a rule, in the shower area, bathrooms, laundries and baths). The ceiling does not need ventilation at all, therefore, it should not be taken into account.
For all the structures of non-ventilated floors presented in the article, including for open beams, wood protection is quite sufficient. paint coatings or other finishes. Special chemicals are not needed here.

Fire protection of floors

Special requirements for building materials and structures are imposed by norms fire protection. All materials are divided into combustible and non-combustible. Structures made of materials of various properties are distinguished, if possible, by delaying fire for some time (semi-fire-resistant) and completely preventing the spread of fire (fire-resistant). These characteristics are fixed in building codes.
In residential construction, in particular, in buildings where the floor of the upper floor is located more than 7 m from ground level, the structures of the interfloor floor must have at least fire-retarding properties (the duration of fire resistance is at least 30 minutes under experimental conditions). For the manufacture of wooden structures, it is allowed to use solid wood and other wood materials of ordinary sizes and density. However, in public buildings, wood is treated with solutions that make it fire resistant. Naturally, non-combustible materials can also be used, in particular, gypsum fiber and gypsum boards.
Typical examples of ceilings made of wooden boards with fire insulation are shown in fig. 12.

When designing ceilings on open wooden beams ( fig. 13), it is also necessary to take into account the fact that these beams are exposed to fire not only from below, but also from the sides.
When determining the resistance parameters of structures made of solid wood (for example, coniferous), its burnout rate is assumed to be 0.8 mm / min.
When calculating floors for open wooden beams 24 cm high with a span width of 5.80 or 5.85 m, the width of the beams is increased to 120 mm or more, so taking into account fire resistance, they must be selected with a cross section of 11x24 cm.
Based on the above, we can conclude that there are still enough questions regarding the reliability of sound insulation and fire safety of ceilings, and in the coming years they will have to be solved by the joint efforts of scientists, designers, manufacturers of building materials, designers and builders.

Increasing the bearing capacity of floor beams

The bearing capacity of floor beams can be increased if necessary. Increasing the cross section of the beams by attaching thick boards to them, the ends of which, like the beams, must lie on the supports, is one of the most common ways to solve this problem.

Rice. 14. .

Can also be used steel channels U-shaped profile, attaching them to the beam on the side with bolts. The advantage of this method is that it will be enough to open the floor beams ("bare") for fastening on only one side.
But, perhaps, the simplest, but requiring serious labor, will be to strengthen the overlap by laying additional beams (between the existing ones) that cover the span from support to support.
In most old houses, the section of the floor beams is sufficient (and even with a margin) and they are laid with a small step, which indicates good construction.
The condition of the beams and floors must be checked in any case. Beams damaged by pests and moisture, and therefore weakened, should be strengthened.
With prolonged exposure to moisture due to leaks in the area of ​​​​overhangs, damage to the heads of the beams on the supports is not excluded. In this case, it is better to remove the damaged part of the beam to healthy wood, and reinforce and lengthen the remaining part with overlays from sufficiently thick boards that provide the required strength.

A clean floor and filing are elements of an interfloor overlap, but they belong to the category of finishing work. Therefore, we will talk about them in the next article.

Comments:

There are interfloor, basement, basement and attic floors. over wooden beams is a system in which logs are stacked in the right position and at a certain distance from each other.

Advantages and disadvantages of the design

The installation of wooden floor beams is intended for private houses that have only one floor, or for buildings erected along frame technology. The maximum span for such a device is 5 m.

Concerning positive aspects, then the following can be distinguished:

1. To install a wooden floor, you do not need to spend a lot of time, because in this case, equipment is not needed due to the light weight of the wood.
2. Despite the fact that wood is a natural material, it has a low cost, unlike reinforced concrete slabs.

But there are also disadvantages in this arrangement:

1. So that wooden beams do not succumb to rot, mold and moisture, before installation, it is necessary to impregnate the beams with special means.
2. In terms of fire hazard, wood has a high rate for this characteristic.

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How to make calculations correctly?

Pine, spruce or larch beams may be suitable for arranging a wooden floor. But, regardless of what kind of wood will be used for these purposes, you need to know that the moisture index should have a maximum rating of 14%. Otherwise, the elements will have insufficient strength, during installation and further operation, the structure will sag.

The distance from the laid elements should not exceed 1 m, so that the strength indicator is optimal. For additional reinforcement, metal beams or thick boards are used, but these elements will increase the load on the walls of the house and on its foundation.

You should know that if you compare a beam with a round log, then the second one is more tolerant of loads, although the beam itself does not bend so much. If two beams are fastened together with a bolt, then they will be more reliable than two elements simply placed next to each other.

The installation of a wooden floor comes with the expectation that each beam has a deflection, the minimum indicator of which can be 1/300 of its length. Therefore, a construction lift is used, which allows to compensate for such deformation. In this case, the beam structure will have an upwardly curved middle, which will later level out under the influence of loads.

The correct beam should have a thickness of not less than 1/24 of its length.

If necessary, replace one wooden beam two boards are used, which are fastened together. Only their total cross section should be equal to the cross section of the beam.

To fasten the elements, nails and self-tapping screws are used, which have a step of 20 cm and are arranged in a checkerboard pattern.

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Creating a slab

Before making a wooden floor, it is necessary to treat the ends of the beams with an antiseptic. They are also tarred and wrapped with roofing material in two layers.

The ends of the beams are attached to the walls.

If work is carried out with attic floor, then the bars will be fixed on the last crown of the log or lumber wall, where openings are prepared in advance for the entire thickness of the surface.

Depending on the type of construction, several types of fasteners can be used:

You can also use the dovetail mount, using metal brackets.

This method is suitable for buildings made of timber. If the installation is in wooden house, then here the method of fastening to the crossbar using trapezoidal joints, which are reinforced with clamps, is more common. Both methods create a single level between the crossbar and the beam.

The easiest thing that can be done in fastening beams and crossbars is done as follows: cranial bars are mounted on the crossbars, and a beam is already installed on top of them. Such bars are needed with a section of 5x5 cm.

When wooden beams are laid in a panel house, the beams can be mounted directly on the wall itself or in pre-made nests in it.

The ends of the beams are placed in them. It is important to know here that each niche should be on the same level as the others, and its depth should be equal to 15-20 cm. As for the width, gaps of 1 cm are left here so that ventilation is carried out. This is done so that the beams do not rot. As soon as the beam is in its place, it is covered with tow.

There is another way to secure the beams in place: this is the use of metal anchors. This element is inserted into the socket at one end, and the other end is mounted with screws to the crossbar. With this installation, the beam will not enter the wall.

For brick buildings, a wooden floor is installed on the walls or in special holes (nests).

It is also important to keep one level for such niches, for which the bottom is leveled with a concrete solution. As soon as the mixture dries, the bottom is covered with a double layer of roofing material or roofing felt.

In this case, when creating nests for the beams, it is necessary that their width be 6-10 cm larger than the crossbar, so that after installation there are gaps of 3-5 cm. The depth of such a hole should be 20-25 cm, while the installation does not go up to the very end, and so that 3-5 cm remain to the bottom. The beams from the ends are treated with antiseptics, after which they are tarred and covered with hot bitumen. In this case, it is necessary that the end cut remains intact. Having wrapped the element with a two-layer roofing felt or glassine (with an open end), it is inserted into its place. At the end, the niches are filled with concrete-crushed stone mortar and leveled to the level of the wall.

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Roll-on flooring: features

To create the ceiling of the lower floor, it is necessary to roll up the floor. There are several ways to do this, but the simplest one will be discussed below.

Cranial bars (section 4x4 or 5x5 cm) are attached to the installed beam along the sides. Thus, the bottom of the bars will be flush with the bottom of the beam. For rolling, boards (1-2.5 cm) are used, which must be laid on the cranial elements with a transverse direction relative to the beams.

It is important that there are no gaps between them. Plywood or ready-made wood panels are also suitable for these purposes. To level the ceiling from below, you can use LGK or the same plywood 0.8 cm thick.

You can roll up using a slab or a beam with a cross section of 6 cm or more. In this case, you will need the same cranial bars as in the previous case. Against the direction of the beams, on top of the bars, a slab is spread, but so that it looks up with its rounded side. Further, the “quarter” method is used for the connection, for which grooves are made in the beam. When choosing a slab, you need to know that its thickness should help create one level between the bottom of the beam and the material, while contributing to a reliable connection with the cranial elements. In this case, the slab will play the role of not only rolling, but also filing.

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